How to avoid shark attacks

The Cape Cod National Seashore released an advisory to swimmers that mirrored other expert advice: Don't swim alone in the ocean at dawn or dusk; stay close to shore where your feet can touch the bottom; limit splashing and don't wear shiny jewelry.

George Burgess, director of the Florida Program for Shark Research, isn't sure there is a quantifiable sixth sense that tells humans when sharks might be in the water, but he can't discount the years of ocean experience that might tell surfers and other water enthusiasts that something is wrong.

"They can notice something that doesn't seem quite right. It's like a sailor being able to forecast a storm at sea," said Burgess, who is also editor of the International Shark Attack File, a website that tracks shark attacks worldwide.

As rare as they are — there have only been two great white shark attacks in the last 77 years in Massachusetts — more sharks are coming to Cape waters every year to feed on a rapidly expanding seal population. For those not blessed with a sixth sense, or even for those who think they are, there are guidelines that will help to avoid falling victim to a shark.

On Thursday, the Cape Cod National Seashore released an advisory to swimmers that mirrored much of Burgess' advice: Don't swim alone in the ocean at dawn or dusk; stay close to shore where your feet can touch the bottom; limit splashing and don't wear shiny jewelry.

"There have been instances where a swimming dog has attracted a shark. They aren't good swimmers and make a ruckus," Burgess said.

"Staying in groups is a good concept," he said. "Attacks most often occur on people who have moved away from the group."

Getting out of the water when seals are present — which is tough given their wide presence off the Lower Cape — is another way to protect yourself.

"Sea mammals are like magnets to sharks. If you want to reduce your odds of an encounter, it would be smart to get out of the water," Burgess said.

Other experts suggest avoiding murky water and sandbars and beaches where seals are known to haul out, even if you aren't swimming or surfing near them.

John McCosker, senior scientist and chairman of aquatic biology at the California Academy of Sciences in San Francisco, said his studies showed that great whites seemed to prefer attacking surfers on shorter boards, or bodyboards, as opposed to the old-style longboard, or kayaks and windsurfers, although there have been documented attacks on all of them.

And Burgess thinks black wetsuits make people look like seals and could attract a shark.

"Those sharks are going after dark-colored prey," Burgess said. He thinks it would be better if wetsuits were patterned like fish — dark on top and lighter on the front and sides. But that could run up against advice from other experts to not wear contrasting colors that could draw great whites, which are naturally inquisitive.

There are new Australian wetsuits that mimic the bright colors of poisonous species like sea snakes and lionfish. Unfortunately, as some shark scientists point out, some man-eating shark species happen to like both those items.